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Thoracic damping and the relationship between PENH of the thoracic air-flow (IT) and tidal midexpiratory flow (EF50).

Frazer DG; Reynolds JS; Goldsmith WT; McKinney WG; Jackson MC; Afshari AA
Toxicologist 2011 Mar; 120(Suppl 2):493-494
The thoracic air-flow pattern can be modeled as a response to the action of the respiratory muscles. That response can be viewed as being either under-damped, when IT is initially higher then decays toward the end of exhalation, or damped when IT is initially lower and then rises toward the end of exhalation. Both Penh(IT) and the EF50 tend to decrease as IT damping increases. Previously, it has been reported that the EF50 is reduced when pulmonary conductance, 1/RL, decreases (Glaab et al., Am J Physiol. Lung Cell Mol. Physiol., 2001). In addition, it has been shown that exposure to an inhaled intervention causes an increase in Penh(IBOX) where IBOX represents airflow into and out of a whole body plethysmograph. The increase in Penh(IBOX) results in the Penh(IT) versus RawCG relationship moving upward and to the right (Frazer et al., J. Tox. and Eviron. Health, 2010). Several authors have provided evidence that not all increases in Penh(IBOX) are caused by an increase in RawCG (Bates et al., Am. J. of Respir. Cell and Mol. Biology, 2004). It can be shown theoretically, however, that an increase in damping of the IT waveform following an intervention, in cases where Penh(IBOX) increases, results in a reduction in Penh(IT) and indicates an increase in RawCG (SRAW). A decrease in the EF50 can also be shown to be related to a decrease in IT damping.
Biological-effects; Cell-biology; Cell-morphology; Cytology; Inhalants; Laboratory-testing; Lung-irritants; Lung-tissue; Molecular-biology; Pulmonary-disorders; Quantitative-analysis; Respiratory-hypersensitivity; Respiratory-irritants; Statistical-analysis; Tissue-disorders
Publication Date
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NIOSH Division
Priority Area
Construction; Manufacturing
Source Name
The Toxicologist. Society of Toxicology 50th Annual Meeting and ToxExpo, March 6-10, 2011, Washington, DC
Page last reviewed: March 18, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division